Discussions on using the professional data recovery program R-STUDIO for RAID re-construction, NAS recovery, and recovery of various disk and volume managers: Windows storage spaces, Apple volumes, and Linux Logical Volume Manager.

I am trying to recover data from a LaCie Bigdisk Extreme which contains two 250Gb drives. It went faulty due the (apparently infamous faulty power supply). I have removed the two drives and have them both connected on USB to the computer.

I can see the one drive in R-Studio OK with it's partition but only the drive is seen on the other one, no partition is seen. I have scanned that drive and the results show a lot of recognised data areas.

I don't know how to proceed next to try and repair the second drive so the partition can be seen and so it can then be added to the virtual array to recover the data.

You don't have to find a partition on the second drive. Just add the drive to the virtual RAID0.
In fact, the partition is placed on the both drives of your RAID0. The boot record and file table of the partition are on the first drive, so R-Studio has found it and recognized a partition on the drive.

RAID0 is suitable only for high-speed access to temporary files. If you need high speed and reasonable reliability in data storage, use RAID5. Given the cost of modern high-capacity drives, it's not a big deal when compared with the cost of data stored on it.